A superinfection is a second

infection An infection is the invasion of tissues by pathogens, their multiplication, and the reaction of host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmissible disease or communicable d ...

superimposed on an earlier one, especially by a different microbial agent of exogenous or endogenous origin, that is resistant to the treatment being used against the first infection. Examples of this in

bacteriology Bacteriology is the branch and specialty of biology that studies the morphology, ecology, genetics and biochemistry of bacteria as well as many other aspects related to them. This subdivision of microbiology involves the identification, classific ...

are the overgrowth of endogenous ''

Clostridium difficile ''Clostridioides difficile'' (syn. ''Clostridium difficile'') is a bacterium that is well known for causing serious diarrheal infections, and may also cause colon cancer. Also known as ''C. difficile'', or ''C. diff'' (), is Gram-positive spec ...

'' that occurs following treatment with a

broad-spectrum antibiotic A broad-spectrum antibiotic is an antibiotic that acts on the two major bacterial groups, Gram-positive and Gram-negative, or any antibiotic that acts against a wide range of disease-causing bacteria. These medications are used when a bacterial inf ...

, and

pneumonia Pneumonia is an inflammatory condition of the lung primarily affecting the small air sacs known as alveoli. Symptoms typically include some combination of productive or dry cough, chest pain, fever, and difficulty breathing. The severi ...

sepsis Sepsis, formerly known as septicemia (septicaemia in British English) or blood poisoning, is a life-threatening condition that arises when the body's response to infection causes injury to its own tissues and organs. This initial stage is foll ...

from ''

Pseudomonas aeruginosa ''Pseudomonas aeruginosa'' is a common encapsulated, gram-negative, aerobic– facultatively anaerobic, rod-shaped bacterium that can cause disease in plants and animals, including humans. A species of considerable medical importance, ''P. aer ...

'' in some

immunocompromised Immunodeficiency, also known as immunocompromisation, is a state in which the immune system's ability to fight infectious diseases and cancer is compromised or entirely absent. Most cases are acquired ("secondary") due to extrinsic factors that a ...

patients. In

virology Virology is the scientific study of biological viruses. It is a subfield of microbiology that focuses on their detection, structure, classification and evolution, their methods of infection and exploitation of host cells for reproduction, th ...

, the definition is slightly different. Superinfection is the process by which a cell that has previously been infected by one

virus A virus is a wikt:submicroscopic, submicroscopic infectious agent that replicates only inside the living Cell (biology), cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and ...

gets co-infected with a different strain of the virus, or another virus, at a later point in time. In some cases viral superinfections may be resistant to the

antiviral drug Antiviral drugs are a class of medication used for treating viral infections. Most antivirals target specific viruses, while a broad-spectrum antiviral is effective against a wide range of viruses. Unlike most antibiotics, antiviral drugs d ...

or drugs that were being used to treat the original infection. Viral superinfections may also be less susceptible to the host's immune response. In Zika virus infection, there is some evidence that primary infection of another ''Flavivirus'', Binjari virus, results in the direct inhibition of a secondary infection of Zika virus in mosquito cells. Recent metagenomic analyses have demonstrated that the novel coronavirus,

SARS-CoV-2 Severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2) is a strain of coronavirus that causes COVID-19 (coronavirus disease 2019), the respiratory illness responsible for the ongoing COVID-19 pandemic. The virus previously had a No ...

can be associated with superinfection and colonization of other pathogens, such as rhinovirus species and ''Moraxella spp.'' In

parasitology Parasitology is the study of parasites, their hosts, and the relationship between them. As a biological discipline, the scope of parasitology is not determined by the organism or environment in question but by their way of life. This means it f ...

, superinfection is reinfection of the same genus of

parasite Parasitism is a Symbiosis, close relationship between species, where one organism, the parasite, lives on or inside another organism, the Host (biology), host, causing it some harm, and is Adaptation, adapted structurally to this way of lif ...

, as a person infected by '' Fasciola hepatica'' again infected by '' Fasciola gigantica''.

References

Virology {{infectious-disease-stub

See also

References